Sometimes a film or television show will leave ripples in pop culture larger than itself. Take “Star Trek,” for example. The show was only on for three years back in the 1960s, but it has spawned a media empire, including ten films and four new series. The same thing has happened with “Scream,” to a lesser degree.

There were only three “Scream” films, and they fell in quality quickly from number one to number three. This so-so string of horror flicks spawned the “Scary Movie” franchise, which now has more movies to its name.

“Scary Movie 4” reunites perky Anna Faris with her “Scary Movie 3” director David Zucker, who cut his teeth on spoof movies in the 1980s with “Airplane!,” “The Naked Gun” and “Top Secret.” Ultimately, Zucker knows what he’s doing with this film, and there are some funny scenes, but the whole spoof movie genre is starting to fall apart altogether.

Yes, “Scary Movie 4” is better than “Date Movie,” but not by much. It’s comparable to the previous “Scary Movie 3,” but slightly less funny.

One downfall of “Scary Movie 4” is that it is less about Anna Faris’s character of Cindy Campbell and more about Craig Bierko’s character of Tom Ryan. I have a soft spot in my heart for Faris, who is not just a beautiful girl but a good actress with a tremendous sense of humor and comic timing. I don’t have anything against Bierko… except that he’s not Anna Faris.

Like “Scary Movie 3,” the writing is a scattershot of movie references. It doesn’t just include scary movies. In fact, it’s pretty weak on scary movies. The only major horror films it takes on are “The Grudge” and “Saw.” These spoofs are done pretty well, but it leaves so many great targets out. Scary movie milestones like “Cabin Fever” and “28 Days Later” are left behind, as are all the crappy horror films that were released in 2005.

Instead, “Scary Movie 4” goes after pop culture. It’s biggest target is “War of the Worlds,” which I guess is a scary movie in itself, but ultimately it’s a sci fi flick. It also skewers the Oscar winners with some deft send-ups of “Million Dollar Baby” and (as if you couldn’t guess) “Brokeback Mountain.”

Actually one of the biggest targets of “Scary Movie 4” isn’t a movie at all. It’s Tom Cruise, which is why Bierko gets so much screen time. Outside of Anna Faris’s slapstick sequences, the best parts of the film come from frequent Zucker collaborator Leslie Neilsen as President Harris.

The biggest problem any audience will have with these films is that they need to know what is being spoofed. If you haven’t seen “War of the Worlds,” “The Grudge” or “Million Dollar Baby,” parts of the movie just aren’t going to make any sense.

This is a problem with one major scene, which we’ve seen from the trailers, in which Bierko’s Tom Ryan makes an appearance on “Oprah” to declare his love for Cindy Campbell. If you haven’t seen Tom Cruise’s conniption fit he actually had on “Oprah,” you won’t get the joke. Trust me, though. It’s worth searching the internet for that “Oprah” clip. If there’s anything I’ve learned after watching it, it’s that – all movie spoofs aside – Cruise has gone completely insane.

The “Scary Movie” franchise is running out of steam pretty fast. They’re still funny, and the gags still work. But there’s only so far you can go with it.